[Users] compilation on marenostrum 4

[Miguel Zilhão]

hi all,

i've been compiling the latest ET on marenostrum 4, and there were a couple of issues i'd like to ask:

1. on marenostrum, they bundle a lot of mpi-related tools on modules. in particular, one of the 
default modules that is loaded is called 'impi'. this module sets the global variable $MPI to 'impi', ie

  $ echo $MPI
    impi

this seems to severely interfere with the Cactus building process. at the configuration stage i get 
the following:

Configuring with flesh MPI
   Warning: use of flesh MPI via MPI option is deprecated and should be replaced with the thorn 
ExternalLibraries/MPI and its MPI_DIR option
   MPI selected, but no known MPI method - what is "impi" ?

to workaround this problem, i've unloaded the module (module unload impi), which undefines the $MPI 
variable. after this, the configuration stage works fine.
this seems to me like a bug, though. after all, a cluster-wide global variable called $MPI seems 
like a natural thing to exist in a lot of these machines... should the building of Cactus rely on 
the non-existence of such a variable?

the other inconvenient thing is that, by unloading the impi module, one also removes from $PATH the 
mpirun command. so one has to unload the module for compiling the code, and then load it back to be 
able to run it.

2. i was not able to compile with any of the provided intel compilers (with gcc it worked fine). i 
know there are known issues with some versions of the intel compilers; is there some sort of list of 
intel compilers that are known to work? i could maybe try to ask the technical support if they could 
make those specific versions available...

thanks,
Miguel